Conventionally, a scanner for moving a filter test device in XY directions to perform scanning is mounted on a filter support frame on both sides of a single filter so as to straddle the filter. When so mounted, the filter test device scans the exit surface of the straddled filter (e.g., see Patent Document 1).
There are also devices in which a scanner movable in the XY directions or provided with a movable arm is placed on a cart that travels on the floor, and a filter test device is used to scan the exit surface of filters above the cart using the scanner mounted on the cart (refer, e.g., Patent Document 2 and Patent Document 3).
Patent Document 1: Japanese Patent Publication No. 3-50210    Patent Document 2: Japanese Patent Publication No. 5-10605    Patent Document 3: Japanese Laid-open Patent Application No. 63-7820